fs/gfs2/ops_export.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/gfs2_ondisk.h>
  16 #include <linux/crc32.h>
  17 #include <asm/semaphore.h>
  18
  19 #include "gfs2.h"
  20 #include "lm_interface.h"
  21 #include "incore.h"
  22 #include "dir.h"
  23 #include "glock.h"
  24 #include "glops.h"
  25 #include "inode.h"
  26 #include "ops_export.h"
  27 #include "rgrp.h"
  28 #include "util.h"
  29
  30 static struct dentry *gfs2_decode_fh(struct super_block *sb,
  31                                      __u32 *fh,
  32                                      int fh_len,
  33                                      int fh_type,
  34                                      int (*acceptable)(void *context,
  35                                                        struct dentry *dentry),
  36                                      void *context)
  37 {
  38         struct gfs2_inum this, parent;
  39
  40         if (fh_type != fh_len)
  41                 return NULL;
  42
  43         memset(&parent, 0, sizeof(struct gfs2_inum));
  44
  45         switch (fh_type) {
  46         case 8:
  47                 parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
  48                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  49                 parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
  50                 parent.no_addr |= be32_to_cpu(fh[7]);
  51         case 4:
  52                 this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
  53                 this.no_formal_ino |= be32_to_cpu(fh[1]);
  54                 this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
  55                 this.no_addr |= be32_to_cpu(fh[3]);
  56                 break;
  57         default:
  58                 return NULL;
  59         }
  60
  61         return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
  62                                                     acceptable, context);
  63 }
  64
  65 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  66                           int connectable)
  67 {
  68         struct inode *inode = dentry->d_inode;
  69         struct super_block *sb = inode->i_sb;
  70         struct gfs2_inode *ip = inode->u.generic_ip;
  71
  72         if (*len < 4 || (connectable && *len < 8))
  73                 return 255;
  74
  75         fh[0] = ip->i_num.no_formal_ino >> 32;
  76         fh[0] = cpu_to_be32(fh[0]);
  77         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  78         fh[1] = cpu_to_be32(fh[1]);
  79         fh[2] = ip->i_num.no_addr >> 32;
  80         fh[2] = cpu_to_be32(fh[2]);
  81         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  82         fh[3] = cpu_to_be32(fh[3]);
  83         *len = 4;
  84
  85         if (!connectable || inode == sb->s_root->d_inode)
  86                 return *len;
  87
  88         spin_lock(&dentry->d_lock);
  89         inode = dentry->d_parent->d_inode;
  90         ip = inode->u.generic_ip;
  91         gfs2_inode_hold(ip);
  92         spin_unlock(&dentry->d_lock);
  93
  94         fh[4] = ip->i_num.no_formal_ino >> 32;
  95         fh[4] = cpu_to_be32(fh[4]);
  96         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  97         fh[5] = cpu_to_be32(fh[5]);
  98         fh[6] = ip->i_num.no_addr >> 32;
  99         fh[6] = cpu_to_be32(fh[6]);
 100         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
 101         fh[7] = cpu_to_be32(fh[7]);
 102         *len = 8;
 103
 104         gfs2_inode_put(ip);
 105
 106         return *len;
 107 }
 108
 109 struct get_name_filldir {
 110         struct gfs2_inum inum;
 111         char *name;
 112 };
 113
 114 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 115                             uint64_t offset, struct gfs2_inum *inum,
 116                             unsigned int type)
 117 {
 118         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 119
 120         if (!gfs2_inum_equal(inum, &gnfd->inum))
 121                 return 0;
 122
 123         memcpy(gnfd->name, name, length);
 124         gnfd->name[length] = 0;
 125
 126         return 1;
 127 }
 128
 129 static int gfs2_get_name(struct dentry *parent, char *name,
 130                          struct dentry *child)
 131 {
 132         struct inode *dir = parent->d_inode;
 133         struct inode *inode = child->d_inode;
 134         struct gfs2_inode *dip, *ip;
 135         struct get_name_filldir gnfd;
 136         struct gfs2_holder gh;
 137         uint64_t offset = 0;
 138         int error;
 139
 140         if (!dir)
 141                 return -EINVAL;
 142
 143         if (!S_ISDIR(dir->i_mode) || !inode)
 144                 return -EINVAL;
 145
 146         dip = dir->u.generic_ip;
 147         ip = inode->u.generic_ip;
 148
 149         *name = 0;
 150         gnfd.inum = ip->i_num;
 151         gnfd.name = name;
 152
 153         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 154         if (error)
 155                 return error;
 156
 157         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 158
 159         gfs2_glock_dq_uninit(&gh);
 160
 161         if (!error && !*name)
 162                 error = -ENOENT;
 163
 164         return error;
 165 }
 166
 167 static struct dentry *gfs2_get_parent(struct dentry *child)
 168 {
 169         struct qstr dotdot;
 170         struct inode *inode;
 171         struct dentry *dentry;
 172
 173         gfs2_str2qstr(&dotdot, "..");
 174         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 175
 176         if (!inode)
 177                 return ERR_PTR(-ENOENT);
 178         if (IS_ERR(inode))
 179                 return ERR_PTR(PTR_ERR(inode));
 180
 181         dentry = d_alloc_anon(inode);
 182         if (!dentry) {
 183                 iput(inode);
 184                 return ERR_PTR(-ENOMEM);
 185         }
 186
 187         return dentry;
 188 }
 189
 190 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
 191 {
 192         struct gfs2_sbd *sdp = sb->s_fs_info;
 193         struct gfs2_inum *inum = (struct gfs2_inum *)inum_p;
 194         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 195         struct gfs2_rgrpd *rgd;
 196         struct gfs2_inode *ip;
 197         struct inode *inode;
 198         struct dentry *dentry;
 199         int error;
 200
 201         /* System files? */
 202
 203         inode = gfs2_iget(sb, inum);
 204         if (inode) {
 205                 ip = inode->u.generic_ip;
 206                 if (ip->i_num.no_formal_ino != inum->no_formal_ino) {
 207                         iput(inode);
 208                         return ERR_PTR(-ESTALE);
 209                 }
 210                 goto out_inode;
 211         }
 212
 213         error = gfs2_glock_nq_num(sdp,
 214                                   inum->no_addr, &gfs2_inode_glops,
 215                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 216                                   &i_gh);
 217         if (error)
 218                 return ERR_PTR(error);
 219
 220         error = gfs2_inode_get(i_gh.gh_gl, inum, NO_CREATE, &ip);
 221         if (error)
 222                 goto fail;
 223         if (ip)
 224                 goto out_ip;
 225
 226         error = gfs2_rindex_hold(sdp, &ri_gh);
 227         if (error)
 228                 goto fail;
 229
 230         error = -EINVAL;
 231         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 232         if (!rgd)
 233                 goto fail_rindex;
 234
 235         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 236         if (error)
 237                 goto fail_rindex;
 238
 239         error = -ESTALE;
 240         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 241                 goto fail_rgd;
 242
 243         gfs2_glock_dq_uninit(&rgd_gh);
 244         gfs2_glock_dq_uninit(&ri_gh);
 245
 246         error = gfs2_inode_get(i_gh.gh_gl, inum, CREATE, &ip);
 247         if (error)
 248                 goto fail;
 249
 250         error = gfs2_inode_refresh(ip);
 251         if (error) {
 252                 gfs2_inode_put(ip);
 253                 goto fail;
 254         }
 255
 256  out_ip:
 257         error = -EIO;
 258         if (ip->i_di.di_flags & GFS2_DIF_SYSTEM) {
 259                 gfs2_inode_put(ip);
 260                 goto fail;
 261         }
 262
 263         gfs2_glock_dq_uninit(&i_gh);
 264
 265         inode = gfs2_ip2v(ip);
 266         gfs2_inode_put(ip);
 267
 268         if (!inode)
 269                 return ERR_PTR(-ENOMEM);
 270
 271  out_inode:
 272         dentry = d_alloc_anon(inode);
 273         if (!dentry) {
 274                 iput(inode);
 275                 return ERR_PTR(-ENOMEM);
 276         }
 277
 278         return dentry;
 279
 280  fail_rgd:
 281         gfs2_glock_dq_uninit(&rgd_gh);
 282
 283  fail_rindex:
 284         gfs2_glock_dq_uninit(&ri_gh);
 285
 286  fail:
 287         gfs2_glock_dq_uninit(&i_gh);
 288         return ERR_PTR(error);
 289 }
 290
 291 struct export_operations gfs2_export_ops = {
 292         .decode_fh = gfs2_decode_fh,
 293         .encode_fh = gfs2_encode_fh,
 294         .get_name = gfs2_get_name,
 295         .get_parent = gfs2_get_parent,
 296         .get_dentry = gfs2_get_dentry,
 297 };
 298